Piston with x-shaped grove in the skirt



FIG. 1 is a perspective view of a piston with X-shaped groove in the skirt showing our invention;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front plan view thereof;

FIG. 5 is a rear plan view thereof and a reverse view of FIG. 5;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken line showing portions of a piston with X-shaped grove in the skirt is included for illustrating environmental structure and forms no part of the claimed design. 

The ornamental design for a piston with x-shaped groove in the skirt, as shown and described. 